There are conventionally known image forming apparatuses that can perform conveyed-document reading, that is, that can read a document while conveying it. Such image forming apparatuses are provided with a document conveying unit for conveying a document. A document conveyed to a reading position by the document conveying unit is read by an image reading section (conveyed-document reading is achieved).
In conveyed-document reading, when a document is conveyed, it may skew. If a document skews when conveyed, it is read in a skewed state. Thus, the reading yields a skewed document image. To address this problem, there have been proposed techniques for correcting the skew of read document images (see, for example, predetermined 1 identified below).